[PATCH v18 2/4] iommu/arm-smmu: Add a way for implementations to influence SCTLR

[Jordan Crouse]

From: Rob Clark <robdclark@xxxxxxxxxxxx>

For the Adreno GPU's SMMU, we want SCTLR.HUPCF set to ensure that
pending translations are not terminated on iova fault.  Otherwise
a terminated CP read could hang the GPU by returning invalid
command-stream data.

Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
---

 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 6 ++++++
 drivers/iommu/arm/arm-smmu/arm-smmu.c      | 3 +++
 drivers/iommu/arm/arm-smmu/arm-smmu.h      | 3 +++
 3 files changed, 12 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 1e942eed2dfc..0663d7d26908 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -129,6 +129,12 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 	    (smmu_domain->cfg.fmt == ARM_SMMU_CTX_FMT_AARCH64))
 		pgtbl_cfg->quirks |= IO_PGTABLE_QUIRK_ARM_TTBR1;
 
+	/*
+	 * On the GPU device we want to process subsequent transactions after a
+	 * fault to keep the GPU from hanging
+	 */
+	smmu_domain->cfg.sctlr_set |= ARM_SMMU_SCTLR_HUPCF;
+
 	/*
 	 * Initialize private interface with GPU:
 	 */
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index dad7fa86fbd4..1f06ab219819 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -617,6 +617,9 @@ void arm_smmu_write_context_bank(struct arm_smmu_device *smmu, int idx)
 	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
 		reg |= ARM_SMMU_SCTLR_E;
 
+	reg |= cfg->sctlr_set;
+	reg &= ~cfg->sctlr_clr;
+
 	arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_SCTLR, reg);
 }
 
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
index 6c5ff9999eae..ddf2ca4c923d 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
@@ -144,6 +144,7 @@ enum arm_smmu_cbar_type {
 #define ARM_SMMU_CB_SCTLR		0x0
 #define ARM_SMMU_SCTLR_S1_ASIDPNE	BIT(12)
 #define ARM_SMMU_SCTLR_CFCFG		BIT(7)
+#define ARM_SMMU_SCTLR_HUPCF		BIT(8)
 #define ARM_SMMU_SCTLR_CFIE		BIT(6)
 #define ARM_SMMU_SCTLR_CFRE		BIT(5)
 #define ARM_SMMU_SCTLR_E		BIT(4)
@@ -341,6 +342,8 @@ struct arm_smmu_cfg {
 		u16			asid;
 		u16			vmid;
 	};
+	u32				sctlr_set;    /* extra bits to set in SCTLR */
+	u32				sctlr_clr;    /* bits to mask in SCTLR */
 	enum arm_smmu_cbar_type		cbar;
 	enum arm_smmu_context_fmt	fmt;
 };
-- 
2.25.1